In the graph below, there are an infinite number of possible lines separating the dots from the crosses. For a given line (solid blue), the distances from the line to each point are shown in red. The [i]margin[/i] is the minimum of these distances. The margin is also illustrated by drawing two dotted blue lines, each at a distance of the margin from the separating line.[br][br]The [i]maximal margin classifier[/i] is the separating line that maximizes the margin. Equivalently, the maximal margin classifier is the separating line with the widest possible region between the dotted lines.

Drag the two big circles to move the line: one moves the y-intercept and the other is free to move anywhere to adjust the slope.[br][br]The goal is to find the line that maximizes the margin, which is shown numerically in the blue box at the top.